Bactericidal compositions containing 6-acetoxy - 2,4 - dimethyl-m-dioxane and a formaldehyde donor and products containing such



'US. Cl. 424-27 3 Claims ABSTRACT OF THE DISCLOSURE Volatilebactericidal compositions, and articles such as sheet material,especially paper, packaging material, and the like, carrying orembodying the volatile compositions, the vapors of which are graduallyreleased, in use, to effect destruction of bacteria, fungi and the like.The preferred compositions contain as their essential active ingredientsa mixture of paraformaldehyde, or other active formaldehyde donor, and6-acetoxy-2,4-dimethyl-m-dioxane otherwise known as Dioxin.

The present invention relates to volatile bactericidal compositions, andto articles such as sheet material, espe cially paper, packagingmaterial, and the like, carrying or embodying the volatile compositions,the vapors of which are gradually released, in use, to effectdestruction of bacteria, fungi, and the like. In one of its morespecific aspects, the present invention relates to volatile bactericidalcompositions containing as their essential active ingredients asynergistic combination of paraformaldehyde, or other activeformaldehyde donor, and 6-acetoxy-2,4-dimethyl-m-dioxane or Dioxin(Sindar Corporation).

It has heretofore been suggested to embody volatile bactericidal agentsin sheet material. However, so far as is known, no such material hascome into any significant commercial use. Those materials which havebeen proposed, generally speaking, possessed a number of disadvantagessuch as inadequate bactericidal activity, too rapid dissipation of thevolatile agent utilized, undesirable properties with respect to odor andappearance, as well as others.

It has been found, in accordance with the present invention that sheetmaterials embodying volatile bactericidal agents can be prepared whichhave outstandingly satisfactory properties and characteristics. Theobjectives of this invention are achieved by combining paraformaldehyde,or other active formaldehyde vapor donating agent, with certain knownvolatilizable bactericidal agents, in specified proportions as hereafterdescribed in detail, and embodying them in sheet material, especiallypaper, to provide products which gradually release bactericidal vaporsto effect destruction of bacteria, fungi, and the like, over a prolongedperiod of time at ambient or room temperatures. Exemplary of anotherformaldehyde donor having utility for the purposes of this invention istrioxane.

Paraformaldehyde is known to have excellent bactericidal properties.However, it has certain properties which militate against its use, asthe sole source of formaldehyde vapors, in various environments,especially in sheet material such as paper. Thus for example, theparaformaldehyde volatilizes slowly, its half-life on uncoated paper,for instance, being of the order of several days, and the formaldehydevapors it gives off have a pungent, offensive odor. Furthermore, thereare limitations as to the amount of paraformaldehyde that can beincorporated into paper. Generally speaking, loadings ofparaformaldehyde in panitcd States Patent 3,469fifi2 Patented Sept. 23,1969 per above one gram per square foot produce a dusty, caked effect inthe paper, making it unsatisfactory for most commercial uses.

The bactericidal compositions of the present invention not only enablethe full bactericidal potential of paraformaldehyde, and other activeformaldehyde donors to be realized, but in certain cases greatly enhancetheir bactericidal properties while concomitantly substantiallyeliminating their undesirable properties. The bactericidal agents usedin combination with the formaldehyde donor in accordance with thepractice of this invention, generally speaking, are characterized inthat they are compatible with the formaldehyde donor at ambienttemperatures, having a volatility at said temperatures which issubstantially the same as, or, especially desirably, greater than thatof the formaldehyde donor, and are capable of masking to an appreciableextent the pungent odor of formaldehyde vapors furnished by the donorwhile either itself, or in combination with a suitable deodorant,imparting an agreeable odor to the combination. Exemplary ofbactericidal agents having utility for the purposes of this inventionare Dioxin, ethyl benzoate, methyl benzoate, methyl p-hydroxy-benzoate,and the like. Of the volatile bactericidal agents employed in thecompositions of this invention Dioxin is of especial importance to theattainment of the objectives of this invention.

The proportions of formaldehyde donor used in the bactericidalcompositions of the present invention are variable. Thus, effectiveresults can be attained with compositions having ratios of the donor tovolatile bactericidal agent of from 9:1 to 1:9. Generally speakinghowever, it is preferred to employ formaldehyde donor to volatilebactericidal agent ratios in the range of from about 3:1 to about 1:3,especially desirably from about 2:1 to 1:1.

In accordance with the particularly preferred aspects of this invention,the bactericidal compositions are formulated of an active formaldehydedonor, particularly paraformaldehyde, and Dioxin. The vapors of Dioxin,unlike those of paraformaldehyde, have a relatively agreeable odor. Inaddition, Dioxin volatilizes rapidly, evincing a half-life in uncoatedpaper of the order of about one hour compared to several days in thecase of paraformaldehyde. In addition, as in the case ofparaformaldehyde, there are limitations on the quantity of Dioxin thatcan be loaded into paper. Thus, Dioxin loaded into paper at a level inexcess of one gram per square foot yields a Wet, limp product which isunsuitable for many commercial purposes.

In accordance with the present invention, it has been discovered thatbactericidal compositions formulated of an active formaldehyde donor,such as paraformaldehyde, and Dioxin as taught herein, not only enablethe attainment of combined-weight loadings in paper of paraformaldehydeand Dioxin in excess of one gram per square foot of paper and a gradualrelease, in use, of vapors to provide effective bactericidal action overa prolonged period of time, but, and quite surprisingly, manifestbactericidal action which is greater than the mere total of theindividual effects of the individual ingredients. Furthermore, thecompositions thus formulated have a pleasant odor suggestive of that ofthe vapors of Dioxin. The masking effect of Dioxin of the odor of theparaformaldehyde vapors is in fact so pronounced that the effect isevident long after the bulk of the Dioxin has volatilized. While theactual mechanism of the potentiating or synergistic activity, and odormasking phenomenon, of the paraformaldehyde-Dioxin compositions have notbeen determined, their unique conjoint activity is clearly observable.

The relative proportions of paraformaldehyde to Dioxin employed toattain the aforementioned synergistic effects are somewhat variable.Generally speaking, they are attained with compositions havingconcentrations, basis Weight, [ranging from about 75% ofparaformaldehyde and about 25% of Dioxin to from about 60% of Dioxin andabout 40% of paraformaldehyde, with especially effective results beingattainable at weight concentration in combination ranging from about 55%of paraformaldehyde and 45% of Dioxin to from about 55% of Dioxin andabout 45% paraformaldehyde. It will be understood that concentrations ofparaformaldehyde and Dioxin below or above the ranges just set out willprovide bactericidal activity. However, from the standpoint of certainpractical considerations, especially in utilizing the compositions inconnection with paper or articles formed from paper, the statedconcentrations ranges are preferred. Also, it will be understood thatother compatible, bactericidal agents, in any desired concentration, maybe combined with the paraformaldehyde-Dioxin compositions of thisinvention without impairment of the unique activity of the compositions.

As indicated hereinabove, the volatile bactericidal compositions of thisinvention are especially suitable for use in connection with sheetmaterial such as paper, and articles fabricated therefrom. Whenincorporated into paper, for example, the vapors of the compositions aregradually released in bactericidally effective concentration over aprolonged period under ambient or room conditions. This activity of thecompositions can be effectively utilized in such articles as hospitalbags, liners for trash and disposal cans, disinfecting bags forcontaminated articles including brushes, combs, telephones, and thelike, packaging for sterile objects, hospital shelf liners, and soforth.

The bactericidal compositions can be applied either directly to thepaper in accordance with known paper impregnation techniques, or theycan first be incorporated into a suitable paper coating substance whichis then applied to paper by any of several conventionally used papercoating procedures. In applying the compositions directly to paper, itis advantageous to utilize an openfibre paper of suflicient weight perream to enable an effective quantity of the compositions to beimpregnated therein. Thus, for example, in utilizing a compositioncomprised of paraformaldehyde and Dioxin, especially eifective resultshave been obtained with bleached kraft paper having a weight of from 70to 100 pounds per ream. The paper, whether embodying the compositions,or carrying a paper coating substance in which the com positions havebeen admixed, can be provided with a liner or film base which isessentially resistant, impenetratable or impermeable to the passagetherethrough of the vapors of the volatile bactericidal compositions toinsure that the vapors will not be dissipated into the atmosphere butwill pass from the paper, or the paper coating substance, to areas wherea bactericidal atmosphere is desired. Various materials, includingparaflin and other Waxes, cellulose acetate, polyvinylidene chloride(Saran), ethylene glycol-te-rephthalic acid polymers (Mylar),polyethylene, metal foil such as aluminum foil, and the like, can beused as a liner or film base for this purpose.

The quantity of the volatile bactericidal compositions of this inventionemployed in making bactericidal sheet material, particularly paper, inaccordance with the practice of this invention can be varied withinrelatively wide limits, depending upon the ultimate form of the articleand the use to which the article is put. Thus, for example, lower weightloadings of the compositions may be used with effective results if avapor impervious liner or film base is present on the paper article. Thesame is applicable to articles for use in an enclosed area wheredissipation of the bactericidal vapors into the atmosphere is physicallyprevented or retarded.

Generally speaking, the volatile bactericidal compositions, whenembodied either in the paper per se or a coat- .4 ing substance appliedto paper, are utilized in an amount sufficient to constitute, by weight,from about 0.4 gram to about 2 grams per square foot of paper area, withespecially effective results being obtained with amounts ranging fromabout 1.5 to about 1.8 grams per square foot of paper area. In utilizingcompositions based on paraformaldehyde and Dioxin, especiallysatisfactory results are attainable with Weight loadings ranging fromabout 0.8 to 1 gram of paraformaldehyde and 0.8 to 1 gram of Dioxin persquare foot on bleached kraft paper having a Weight of 70 pounds perream.

In determining the synergistic activity of the paraformaldehyde-Dioxincomposition of this invention, three one square inch pieces of paper,Weight loaded at a level of 1 gram of Dioxin and 0.8 gram ofparaformaldehyde per square foot of area, were placed into separatepetri dishes containing 10 ml. of nutrient agar inoculated with 2 ml. ofa 72 hour subculture of E. coli, the inoculated petri dishes havingfirst been incubated after inoculation at 35 C. for 24 hours. Similarsized pieces of paper, three of which had a weight loading of 1.9 gramsof paraformaldehyde per square foot of area, and the other three ofwhich had a weight loading of 1.9 grams of Dioxin per square foot ofarea, were each placed in separate petri dishes prepared as indicated.After one hour of exposure to the pieces of paper weight loaded asdescribed, the pieces of paper in one set of dishes was removed and thedishes were incubated for 24 hours. One set of three petri dishes wasthen examined. The petri dish which contained the paper loaded with theparafonnaldehyde and Dioxin composition at the level indicated showed akill of 99.9% compared to for the other papers. The same procedure wasfollowed after 3 hours with another set of dishes. The petri dish whichcontained the paraformaldehyde-Dioxin composition showed a kill comparedto a 95 kill for each of the other papers. At 5 hours, theparaformaldehyde-Dioxin composition showed a 100% kill compared to a 92%kill for the other papers.

Additives such as odorants, deodorants, perfumes, and the like, may, ifdesired, be incorporated into the compositions of this invention. Inaddition, other bactericidal or fungicidal agents compatible with thecompositions, may be added where desired.

It should be understood that while the compositions have been describedwith reference to their particular utility in connection with paperarticles, the compositions can be incorporated into such other materialsas plastics, wood, composites, and the like, to produce similar effects.

The following are specific illustrative examples of the compositions ofthis invention:

What is claimed is: 1. A bactericidal paper embodying a bactericidallyeffective concentration of a bactericidal composition containing as itsessential active ingredients a synergistic combination ofparaformaldehyde and 6-acetoxy2,4-dimethylm-dioxane, the concentration,by weight, of paraformaldehyde and said dioxane ranging from about 55%paraformaldehyde and 45% of the said dioxane to about 55% of the saiddioxane and 45% of the paraforrnaldehyde.

2. A bactericidal composition having utility as an impregnant for abactericidal paper comprising a synergistic mixture of paraformaldehydeand 6-acetoxy-2,4-dimethy1- m-dioxane, the concentration, by weight, ofparaformaldehyde and said dioxane in the composition ranging from about55% of paraformaldehyde and 45% of said dioxane to about 45% ofparaformaldehyde and 55% of said dioxane.

3. A bactericidal paper containing a bactericidally effectiveconcentration of a bactericidal composition containing as its essentialactive ingredients a synergistic mixture of paraformaldehyde and6-acetoxy-2,4-dimethyl-mdioxane, the Weight loading of the bactericidalcomposition in the paper ranging from about 0.8 to 1 gram of theparaformaldehyde per square foot of paper area to about 1 to 0.8 gram of6-acetoxy-2,4-dimethyl-m-dioxane per square foot of paper area.

References Cited OTHER REFERENCES Merck Index, 7th edition, (1960), p.772773.

ALBERT T. MEYERS, Primary Examiner S. I. FRIEDMAN, Assistant ExaminerUS. Cl. X.R.

